Tool for grinding contact points



l "Aug. 3 1926.

N. A. ANDERSON TOOL FOR GRINDING CONTACT POINTS Filed June 12 1924 Z I !NVENTOR I ATTORNE Patented Aug. 3,1926.

UNITE STATES NILS ALFRED ANDERSON, 0F BROOKLYN, NEW YORK.

TOOL FOR GRINDING CONTACT POINTS.

Application filed June 12', 1924. Serial No. 719,516.

The contact points used in the ignition devices of automobiles and other gasoline engines, are made originally with flat, smooth, contact surfaces of hard metal and. after continued use, the contact surfaces become pitted, and worn, resulting in imperfect contact being made. As a result, the efiiciency of the engine decreases, due to imperfect ignition. The object of the present invention is to provide a simple and convenient tool in compact form which may be carried in the tool kit of any automobile and which will serve to hold the contact screw of any of the standard ignition devices while a sharpening stone is moved across the surface of the contact point for the purpose of grinding it down to a smooth surface at right angles to the axis of the screw; the accuracy of the grinding operation being controlled by means of tracks against which the sharpening stone engages when the contact point has been ground to the desired level. The tool comprises a base having the guiding tracks arranged along the sides, together with threaded apertures extending through the base and between the tracks, together with one or more sleeves adapted to be screwed into the threaded apertures in the base and adapted to hold the contact screws in various adjusted positions in order to control the height of the contact point in rela- 'tion to the tracks.

In the drawing forming part of this application,

Figure 1 is a plan view of my improved tool,

Figure 2 is a'sectional view taken on the line 22 of Figure 1,

Figure 8 is a cross sectional view taken on the line 8-3 of Figure 2,

Figure 4 is an enlarged elevation of a contact screw taken from the ignition device of an automobile engine, and

Figure 5 is a detail view showing the method of assembling the screw with the sleeve for holding it.

In the drawing I have shown a base 1 which is preferably made of metal and it may take any shape, although the oblong shape indicated in the drawing is the most compact one. I have shown the base shaped at one end to provide a handle 2 by means of which the base may be gripped to hold it while the sharpening stone is applied to the contact point for grinding. Along each side of the base there is a track 3 which I prefer to make separate from the base in order that it may be made of a very hard metal; and these tracks are attached to the base by means of screws 4 passing through threaded apertures in the base and partly through the tracks, and the heads of these screws being countersunk in the recesses 5 at the under side of the base. The top faces of the tracks are to be accurately ground off flat and smooth on a plane at right angles to the several threaded apertures hereinafter described.

The contact screws in different ignition devices on the market are of different length and have diflferent threads andtherefore I provide holding sleeves and nuts to accommodate different sizes of screws. In the form shown in Figure 2 I have shown a sleeve 6 having a bore 7 through which passes the contact screw 8, the hexagonal head 9 resting against one end of the sleeve.

The screw 8 extends in this instance through the sleeve 6 and it is provided with a lock nut 10 on the lower end, which seats against the lower end of the sleeve and holds the screw 8 tightly in place in the sleeve. The 7 sleeve itself is threaded externally to en-- gage the threaded wall of the tapped aperture 11 extending transversely through the base 1 intermediate the side tracks 3. The

sleeve is provided with a head 12 with which it may be grasped for the purpose of screw- 7 portion 17 which extends into the bore 18 of the sleeve let a sufficient distance to receive in its threaded bore 19 the end of the contact screw 13, which latter, in this form,

is not of sutficient length to pass entirely through the sleeve. In this form, a bushing member 16 is inserted into the'bore of the sleeve 14 and the contact screw 13 is screwed into the threaded bore of the bushing until the head or nut 20 of the contact screw seats against one end of the sleeve 1% and the head 21 of the bushing seats against the other end of the sleeve 14. When the parts are V the axis of the screw.

thus assembled the sleeve is screwed into the appropriate threaded aperture 11 in the base until the top of the contact screw is slightly above the plane of the tracks. By provid ing bushings having suitable threads of required length to engage different forms of contact screws the device may be made to take all of the different kinds of contact screws in use in different ignition systems.

In using the devicethe contact screw is assembled in the sleeve in the manner described above and then the sleeve is screwed into the proper threaded aperture in the base until the contact point of the contact screw is. slightly above the plane of the tracks. A small sharpening stone (not shown) is then moved across the face of the contact point to grind down the surface of the latter until the sharpening stone lies flat against the top surfaces of the tracks and when thiscondition is arrived at the top or contact point of the contact screw will. have been faced off flat and at a plane at right angles to The sleeve is adaptedd to be adjusted in the to bring about the correct possition of the contact point in relation to the tracks. When the contact point is comparatively new and high the sleeve will naturally be set at a lower level for the first grinding operation and after the contact point has been worn and reground the sleeve will naturally be adjusted to a higher position in the base to correspond. lVhen a contact point has been ground off in the present tool it will be found that the ignition system of the motor in which it is used will operate more efficiently. The time required to grind. off

or reface the contact point is a matter of a few minutes and the tool may be carried as part of the equipment in automobiles ready for use at any time.

If desired, the contact screw may be screwed directly into the base without the use of a sleeve. In Figures 1 and 2 I have shown tapped apertures 25 into which the contact screw may be directly screwed, leaving its contact surface projecting slightly above the plane of the tracks to allow the top to be slightlywgronnd down in the refacing operation. NVh-ere the screws are to be applied directly in the base the latter must have threaded apertures suitable for various kinds of screws, but with the use of sleeves it is not necessary to have a multiplicity of threaded apertures in the base to accommodate different sized a-nddilferently threaded screws as this is taken care of by the sleeve. And if new sizes of screws come into use it is only necessary at most to provide a new sleeve to accommodate them.

lilaving described my invention what I claianis:

A too. for regrinding contact screws comprising a base having tracks to control the operation of a grinding stone, said base having threaded aperture arranged between said track", and a sleeve threaded exterior-1y to screw into said aperture and having a bore into which a contact screw is adapted to be inserted, and a nut having a portion adapted to project into the bore of said sleeve and having a threaded bore to receive the contact screw, for the purpose set forth.

Signed at the city, county and State of New York, this 4th day of June, 19:24.

nits A. Assessor. 

